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摘要： Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999. 1 public class Solution { 2 public int ... 阅读全文

摘要： Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.public class Solution { public String int... 阅读全文

摘要： Implementatoito convert a string to an integer.Hint:Carefully consider all possible input cases. If you want a challenge, please do not see below and ... 阅读全文

摘要： Given an arraySofnintegers, are there elementsa,b,c, anddinSsuch thata+b+c+d= target? Find all unique quadruplets in the array which gives the sum of ... 阅读全文

摘要： Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two nu... 阅读全文

摘要： Given an arraySofnintegers, are there elementsa,b,cinSsuch thata+b+c= 0? Find all unique triplets in the array which gives the sum of zero.Note:Elemen... 阅读全文

摘要： The set[1,2,3,…,n]contains a total ofn! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie... 阅读全文

摘要： You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single ... 阅读全文

摘要： Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only n... 阅读全文

摘要： Reverse Linked List IIReverse a linked list from positionmton. Do it in-place and in one-pass.For example:Given1->2->3->4->5->NULL,m= 2 andn= 4,return... 阅读全文